An energy watchdog is worried that the popularity of power-hungry gadgets could hurt the environment.

In a report Wednesday, the Paris-based International Energy Agency estimates new electronic gadgets will triple their energy consumption by 2030 to 1,700 terawatt hours, the equivalent of today's home electricity consumption of the United States and Japan combined.

The world would have to build around 200 new nuclear power plants just to power all the TVs, iPods, PCs and other home electronics expected to be plugged in by 2030, when the global electric bill to power them will rise to US$200 billion (NZ$335 billion) a year, the IEA said.

Consumer electronics is "the fastest growing area and it's the area with the least amount of policies in place" to control energy efficiency, said Paul Waide, a senior policy analyst at the IEA.

Electronic gadgets already account for about 15 per cent of household electric consumption, a share that is rising rapidly as the number of these gadgets multiplies. Last year, the world spent US$80 billion on electricity to power all these household electronics, the IEA said.

Most of the increase in consumer electronics will be in developing countries, where economic growth is fastest and ownership rates of gadgets is the lowest, Waide said.

"This will jeopardize efforts to increase energy security and reduce the emission of greenhouse gases" blamed for global warming, the agency said.

Existing technologies could slash gadgets' energy consumption by more than 30 per cent at no cost or by more than 50 per cent at a small cost, the IEA estimates, meaning total greenhouse gas emissions from households' electronic gadgets could be held stable at around 500 million tons of CO2 per year.

If nothing is done, this figure will double to around 1 billion tons of CO2 per year by 2030, the IEA estimates.

Televisions are one area where much improvement could be made, Waide said.

The IEA estimates the world will soon have 2 billion TVs in use – or an average of 1.3 televisions for every household with electricity.

In addition to becoming more numerous, TVs are also getting bigger screens and are being left on for longer each day. The group predicts 5 per cent annual increase in energy consumption between 1990 and 2030, just from TVs alone.

Waide said simple measures, such as allowing consumers to regulate the energy consumption of their gadgets according to the features they actually use, should be adopted to counter this growth.

He said governments also need to encourage minimum performance standards and easy-to-read energy labels, so consumers can take energy efficiency into account along with price when buying home electronics.